A volcano is an opening in the Earth’s crust that allows molten rock, volcanic ash, and gases to escape from a magma chamber beneath the surface. While many associate volcanoes with dramatic eruptions, the question of whether Texas has active volcanoes requires examining its deep geological history.
Texas’s Volcanic Past
Texas experienced significant volcanic activity millions of years ago, leaving numerous geological remnants across the state. During the Late Cretaceous Period, approximately 83 to 79 million years ago, a series of submarine volcanoes erupted in what was then a shallow sea covering much of Central Texas. Pilot Knob, near Austin, is a prominent example of these ancient underwater volcanoes, representing the eroded core of a once-active volcanic system.
This period of volcanism in Central Texas formed around 75 to 200 individual volcanoes, stretching from areas near Waco, through Austin and San Antonio, down to Del Rio and Uvalde. These eruptions spewed ash and sediments into the water, creating ash cones. Today, features like Pilot Knob are the weathered remains of these ancient structures, with evidence of volcanic ash and basaltic rock still visible in places like McKinney Falls State Park.
Further west, in the Trans-Pecos region, a later and distinct period of volcanism occurred between about 48 and 17 million years ago. This activity shaped much of the rugged landscape seen today in areas such as the Davis Mountains and Big Bend National Park. The Davis Mountains, for instance, were formed by extensive lava flows and eruptions from volcanic centers like the Paisano Volcano and the Buckhorn Caldera, roughly 35 to 38 million years ago.
Big Bend National Park showcases a complex volcanic history, with eruptions occurring between 42 and 32 million years ago within the park boundaries. This activity formed the Chisos Mountains and left behind features such as volcanic dikes, lava domes, and pyroclastic deposits like those found in Tuff Canyon. These diverse formations, including calderas and igneous intrusions, are now preserved as significant geological sites, offering insight into Texas’s fiery past.
Current Geological Stability
Despite its extensive volcanic past, Texas is not currently volcanically active. All the volcanoes found in the state are considered extinct, meaning they no longer have a magma supply and are not expected to erupt again. The last known volcanic eruption in Texas occurred about 30 million years ago in the Trans-Pecos region.
Texas’s present geological stability is largely due to its location far from major tectonic plate boundaries, where most volcanic activity occurs. While minor earthquakes do occur in Texas, particularly in West Texas, they are typically related to movements along fault lines or have been linked to human activities such as the underground injection of wastewater from oil and gas production. These seismic events are distinct from volcanic processes and do not indicate a resurgence of volcanic activity. Therefore, the “volcanoes” seen across Texas today are silent reminders of a distant geological era.